Data storage and retrieval systems are used to store information provided by one or more host computer systems. Such data storage and retrieval systems receive requests to write information to one or more secondary storage devices, and requests to retrieve information from those one or more secondary storage devices. Upon receipt of a write request, the system stores information received from a host computer in a data cache. In certain implementations, a copy of that information is also stored in a nonvolatile storage device. Upon receipt of a read request, the system recalls information from the one or more secondary storage devices and moves that information to the data cache. Thus, the system is continuously moving information to and from storage devices, and to and from the data cache.
If the data disposed in the data cache were written in a first sector format, and if the data disposed in the one or more storage devices were written in a second sector format, then a sector format conversion device would be required. Applicants have found that what is needed is a sector format conversion device that both performs the sector format conversion process and that preserves data integrity during a power loss event. Applicants' apparatus and method preserve data integrity throughout the sector conversion process even during a power failure. In certain embodiments, Applicants' apparatus and method are compliant with the Power Failure Warning protocols under the SFF-8045 Specification.